Assessing the Performance of the EQ-VAS in the NHS PROMs Programme


The study aims to increase knowledge about the performance of the EuroQol-visual analogue scales (EQ-VAS) in the UK NHS patient-reported outcome measures (PROMs) programme, which covers groin hernia, hip and knee replacement and varicose vein surgery, and make suggestions for improved collection, coding and analysis of data.

Four hundred scanned images of matched before-and-after EQ-VAS PROMs responses were selected at random. These were classified according to the different ways in which they were completed. Patient-level PROMs programme data linked to Hospital Episode Statistics for all patients from April 2009 to February 2011 were used to analyse the relationship between the EQ-VAS and the EQ-5D profile, index-weighted profile and condition-specific instruments. The linked PROMs and HES data comprise 331,951 anonymised patient records.

A large majority (95 %) of EQ-VAS responses were completed in an unambiguous way, but only a minority (45 %) conformed strictly to the instructions given, posing challenges for data coding. The EQ-VAS data have a predictable and consistent relationship with the EQ-5D profile, although the correlations between the EQ-VAS and other measures of patient-reported health, both before and after surgery and in the change between them, are weak.

EQ-VAS data might be improved by providing better guidance on collection and coding. It is argued that the observed differences in results from EQ-VAS and other measures of health reflect the fact that it measures a broader underlying construct of health, arguably providing a means of summarising overall health that is closer to the patient’s perspective.
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